For the routing of fluids at relatively high temperature, for example greater than 100.degree. C., and under a high pressure, for example at 8000 kilopascals (80 bars), it is common practice to use hoses connecting, for example, the material outlet of a pumping element placed above the drum of material at the intake of the element for distribution and/or processing of the fluid. By fluid, and in the remainder of this specification, is meant products generally exhibiting a great viscosity such as petroleum oils, thermoplastics, for example with a rubber base or more particularly with a polyisobutylene and/or butyl rubber base, all materials applied particularly in the automobile and glass industries. Practically solid at ambient temperature--a polyisobutylene and/or butyl rubber with a molecular weight of 8000 to 15,000 according to STANDINGER having for example a viscosity close to 115.degree. Mooney at the end of eight hours and at 40.degree. C.--these materials must be worked at temperatures often considerably higher than 100.degree. C.--and then also exert pressures sometimes greater than 30,000 kilopascals. When these fluids are distributed by means of hoses, consisting of rubber tubes inside and outside reinforced with a central metal mesh, for reasons of safety and of technology small-diameter hoses, less than 100 mm, connected at their intake and outlet are used in the following manner. The metal mesh is first of all stripped over several centimeters, then a connecting part consisting of two metal elements is made to penetrate with force with a press. The first element consists of a hollow tube whose outside diameter corresponds to the inside diameter of the hose and with a tapered truncated end. It is extended at its other end by a portion with a larger outside diameter forming a base.
The tube is provided in the vicinity of this base with an outside thread on which is screwed the second element consisting of a flange striking against the base. This flange is extended by a second threaded portion whose inside diameter corresponds to the diameter of the hose. When the connecting part is put in place, an operation that is facilitated by the tapered shape of the tube, this second threaded portion of the flange is screwed to the stripped metal mesh of the hose. In addition, for a better seal, the thread carried by the hollow tube has a length greater than that necessary for the screwing of the flange to the hollow tube, so that the latter is partially screwed into the inside rubber tube of the hose.
Such a connection exhibits a weak point at the level of the tapered end of the hollow tube, the fluid routed by the hose exerting a very great pressure because of the narrowing of the section. Experimentally, breaks of connections have been found for pressures exceeding 8500 kilopascals with hoses of more than 700 mm.sup.2. This technical limitation is all the more bothersome--as previously indicated--as the technology of hoses makes it possible for the same sections to withstand pressures higher than 30,000 kilopascals. In addition, this type of connection has a delicate assembly which can be performed only in a factory. In practice, the manufacturer of hoses provides them with connections, which is not always fully satisfactory for the user (who, for example, for the development of new machines) desires to have connections which he can assemble at will.
A connecting part for a rubber hose is also known from U.S. Pat. No. 2,071,478. This connecting part consists of a first element forming a base on which a valve, for example, is screwed. This tubular element is driven by force into the rubber hose and is provided with teeth which oppose its being pulled out. In addition, its end that penetrates into the rubber hose is slit so as to open in two faces when a second tubular element is introduced into it by screwing on the inside of the first tubular element. To prevent the rubber hose from expanding too much, its end is preferably equipped with a brass collar.
This type of connection brings about a reduction, by more than half, of the passage section for the fluid travelling in the rubber hose. In addition, the second tubular element penetrates inside the rubber hose farther than the first tubular element, so that when the fluid travels in the direction of the base, it exerts a strong pressure on the first tubular element which has a tendency to be ejected. This ejection does not occur when the fluid travels from the base toward the rubber hose, but the connections are necessary at each end of the rubber hose, and this very considerable narrowing of the fluid passage section, a true bottleneck, is still maintained, so that this type of connection does not make it possible to with stand very high pressures much greater than 80 bars, for example.